Marine fuel supply system and a marine craft including same

ABSTRACT

A marine fuel supply system is disclosed in which a salt water sensor is positioned between a fuel reservoir and a pump used to pump fuel from the reservoir to an internal combustion engine. The water sensor is located near to the bottom of a closed vessel forming part of a water separator so as to sense when salt water separated from the fuel has reached a pre-determined level. A signal is then sent to indicator means in the form of an electric lamp and buzzer to warn an operator of the marine craft of the need to drain off the collected salt water.

This invention relates to marine craft such as boats or pleasure craftand in particular to a fuel supply system for such a marine craft.

It is well known to provide a marine craft such as a boat, yacht, dingyor jet-ski with an inboard or outboard internal combustion engine usinga liquid fuel such as petrol, diesel, paraffin or associated fuels.

Such liquid fuels are stored in a reservoir often known as a fuel tankand are supplied to the engine in order to generate power by combustion.

It is a problem in a marine environment that salt water may seep intothe fuel tank thereby contaminating the fuel stored therein. Particularexamples include: salt water entering through deck fittings; refuelingoutlets containing water contaminant; condensation in the vessel tanks;and filling with salt water and/or fresh water by the operator. If wateris present in the fuel then damage to the internal combustion engine canoccur and damage to parts and components including corrosion of the fueltank, the fuel supply lines, fuel pumps, pistons and bore of the engineand, if fitted, fuel injectors is also likely to occur.

In addition, the fuel water mixture can be contaminated with a fungalgrowth that is likely to block or restrict the flow of fuel.

In severe cases hydraulic lock can occur in the engine causing seriousdamage or in the case of fuel injectors the small components are likelyto break.

The failure of such components is potentially a dangerous situation ifthe vessel is out to sea and a total loss of motive power occurs.

It is an object of this invention to provide a means for detecting thepresence of sea water in fuel and indicating the presence to an operatorof the vessel.

According to a first aspect of the invention there is provided a marinefuel supply system to supply liquid fuel to an internal combustionengine of a marine craft, the fuel supply system comprising a reservoirto store the liquid fuel, at least one fuel pump to pump fuel from thereservoir to the engine and at least one sensor located between thereservoir and the engine wherein the or each sensor is arranged todetect the presence of sea water in the fuel and provide an indicationto an operator of the marine craft.

The presence of sea water may be indicated by an audible warning device.

The audible warning device may be a siren or may be a buzzer.

The presence of sea water may be indicated by a visual warning device.

The visual warning device may be an electric light or light emittingdiode.

The indication of the presence of water may be provided to more than onelocation on the marine craft.

The or each sensor may be located between an outlet from the reservoirand an inlet to a fuel pump.

The fuel supply system may further comprise of a fuel filter locatedbetween the fuel pump and the engine.

The system may have a low pressure fuel pump connected to the reservoirand a high pressure fuel pump connected to the low pressure fuel pump tosupply fuel at high pressure to the engine and the or each sensor islocated between the outlet from the reservoir and the low pressure fuelpump.

The fuel filter may be located between the low pressure fuel pump andthe high pressure fuel pump.

The or each sensor may be mounted near to the bottom of a waterseparator used to separate sea water from the liquid fuel.

The water separator may comprise of a closed vessel having an upperwall, a lower wall, at least one side wall, an inlet to the closedvessel and an outlet from the closed vessel.

The inlet to the closed vessel and the outlet from the closed vessel maybe connected to the upper wall of the closed vessel.

There may be at least one baffle plate interposed between the inlet tothe closed vessel and the outlet from the closed vessel.

There may be at least one baffle plate extending downwardly from theupper wall into the closed vessel at a position between the inlet to theclosed vessel and the outlet from the closed vessel.

There may be a baffle plate extending outwardly from the or one sidewall of the closed vessel in close proximity to the outlet from theclosed vessel.

An air bleed device may be fitted to the upper wall.

A drain plug may be fitted to the lower wall of the closed vessel.

At least one sensor may be fitted to the or one of the side walls of theclosed vessel in close proximity to the lower wall.

At least one sensor may be fitted to the lower wall of the closedvessel.

Preferably, the or each sensor may be located such that when sea waterreaches a predetermined level in the closed vessel the indication isprovided to the operator.

According to a second aspect of the invention there is provided a marinecraft having at least one internal combustion engine and at least onefuel supply system in accordance with the first aspect of the invention.

The fuel supply system may be arranged to supply an indication of thepresence of sea water in the fuel to at least two separate craft controlstations.

One of the control stations may be a flying bridge.

The craft may have two control stations and the other control stationmay be a main deck control station.

According to a third aspect of the invention there is provided a waterseparator for use in a marine fuel supply system to separate sea waterfrom fuel comprising a closed vessel having an upper wall, a lower wall,at least one side wall, an inlet to the closed vessel and an outlet fromthe closed vessel.

The inlet and the outlet may be connected to the upper wall of theclosed vessel.

There may be at least one baffle plate interposed between the inlet andthe outlet.

There may be at least one baffle plate extending downwardly from theupper wall into the closed vessel at a position between the inlet to theclosed vessel and the outlet from the closed vessel.

There may be a baffle plate extending outwardly from the or one sidewall of the closed vessel in close proximity to the outlet from theclosed vessel.

An air bleed device may be fitted to the upper wall.

A drain plug may be fitted to the lower wall of the closed vessel.

At least one sensor may be fitted to the or one of the side walls of theclosed vessel in close proximity to the lower wall to detect thepresence of sea water in the closed vessel.

At least one sensor may be fitted to the lower wall of the closed vesselto detect the presence of sea water in the closed vessel.

Preferably, the or each sensor may be located such that when sea waterreaches a pre-determined level in the closed vessel an indication of thepresence of sea water is provided.

The invention will now be described by way of example with reference tothe accompanying drawing of which:—

FIG. 1 is a schematic drawing of a marine fuel supply system accordingto a first aspect of the invention;

FIG. 2 is a cross-section through a water separator forming part of thefuel supply system shown in FIG. 1;

FIG. 3 is an enlarged view of a water sensor forming part of the waterseparator shown in FIG. 2;

FIG. 4 is a circuit diagram of a warning circuit connected to the watersensor shown in FIG. 3; and

FIG. 5 is a dual connector for connecting the water sensor shown in FIG.3 to two separate locations.

With reference to FIG. 1 there is shown a marine fuel supply system tosupply liquid fuel to an internal combustion engine fitted to a marinecraft. The fuel supply system comprises of a reservoir or fuel tank 1 tostore the liquid fuel, a pair of fuel pumps 3, 5 to pump fuel from thereservoir 1 to the engine and a sensor 13 located between the reservoir1 and the engine. The sensor 13 is arranged to detect the presence ofsea water in the fuel and provide an indication to an operator of themarine craft.

The water sensor 13 is located between an outlet from the reservoir 1and an inlet to a low pressure fuel pump 3.

A fuel filter 4 is located between the fuel pump 3 and the engine and asapplied to a diesel engine fuel supply system there is the low pressurefuel pump 3 connected to the reservoir 1 and a high pressure fuel pumpin the form of a diesel distribution pump is connected to the lowpressure fuel pump 3 to supply fuel at high pressure to the engine bymeans of a number of fuel injectors 6 four of which are shown. The watersensor 13 is located between the reservoir 1 and the low pressure fuelpump 3 and the fuel filter 4 is located between the low pressure fuelpump 3 and the high pressure fuel pump 5.

It will be appreciated that all of the components in the fuel supplyline are interconnected by a fuel supply line 30 a, 30 b, 30 c, 30 d andthat unused fuel is returned to the reservoir 1 via a fuel return line31.

As best seen with reference to FIG. 2 the sensor 13 is mounted near tothe bottom of a water separator 2 used to separate sea water from theliquid fuel. The water separator 2 comprises of a closed vessel in theform of a rectangular tank having an upper wall 33 (e.g. of width 14cm), a lower wall 34, four side walls 35 (e.g. of height 10 cm), aninlet 7 to the closed vessel and an outlet 9 from the closed vessel. Theinlet 7 and the outlet 9 are connected to the upper wall 33 of theclosed vessel.

Although the closed vessel is shown as a rectangular tank it willappreciated that it could be of another shape such as for example acylinder closed of at each end by walls in the form of upper and lowerend plates.

There are two baffle plates 10, 11 interposed between the inlet 7 andthe outlet 9. In other embodiments the location of the baffle plates isvaried such as embodiments in which the position of the second baffleplate 11 is as shown in FIG. 2, and the first baffle plate 10 issimilarly upper wall mounted parallel to the second baffle plate 11. Instill further embodiments the baffle plates 10, 11 are omitted, althoughtheir presence is preferred.

A first baffle plate 11 extends downwardly from the upper wall 33 intothe closed vessel at a position between the inlet 7 to the closed vesseland the outlet 9 from the closed vessel. A second baffle plate 10extends outwardly from one side wall 35 of the closed vessel in closeproximity to the outlet 9 from the closed vessel.

The first and second baffle plates 11 and 10 prevent fuel from passingdirectly from the inlet 7 to the outlet 9 and in particular ensure thatany salt water mixed with the fuel has time to settle to the bottom ofthe closed vessel.

The level of salt water trapped in the closed vessel is indicated by theline 12 on FIG. 2 which it will be noted is just above the level of thesensor 13. This level corresponds to a pre-determined level in theclosed vessel at which an indication will be provided by the watersensor 13 to an operator of the marine craft that the level of collectedsalt water has reached a level where draining of the salt water from thewater separator 2 is required.

Although as shown the level is well above the water sensor 13 inpractice as soon as the water sensor 13 is totally immersed in saltwater an indication will be provided.

An air bleed device in the form of an air bleed screw 8 is fitted to theupper wall 33 to allow any air that gathers in the water separator 2 tobe let out.

A drain plug 14 is fitted to the lower wall 34 of the closed vessel topermit salt water collected by the water separator 2 to be drained off.

It will be noted that the sensor 13 is fitted to one of the side walls35 of the closed vessel in close proximity to the lower wall 34 (e.g. 1to 3 cm from lower wall) this is in order to maximise the usable volumeof the closed vessel while providing sufficient capacity in the waterseparator 2 for the storage of salt water so that the water separator 2does not need to be emptied too often. If the sensor 13 is mounted toohigh in the water separator 2 there is a risk that some of the saltwater extracted from the fuel could be re-absorbed.

It will be appreciated that the sensor 13 could be fitted to the lowerwall 34 of the closed vessel and project upwardly therefrom. It will befurther appreciated that in either case more than one water sensor couldbe used if a fail safe system is required.

FIG. 3 shows the water sensor 13 in more detail and it can be seen thatthe water sensor 13 has a threaded shank 15 which is engaged in a holein the side wall 35 of the closed vessel and is held in place by a nut(not shown) and that a seal 16 is provided to produce a seal between thewater sensor 13 and the respective side wall 35.

The water sensor 13 has an electrical socket 17 a formed as an integralpart thereof for co-operation with a plug 17 b forming part of anindication circuit shown in greater detail in FIG. 4. A cable 17 cextends away from the plug 17 b and contains three leads, a ‘−ve’ orearth lead, a ‘+ve’ power lead and a ‘+ve’ signal lead. The other end ofthe cable 17 c is terminated in a further plug (not shown) which isidentical to the plug 17 b and is arranged for connection to a socket 23having three terminals and forms part of the indication circuit.

As best understood with reference to FIG. 4 the indication circuitcomprises of a source of electrical power in the form of a battery 19having a negative terminal connected to earth by an earth lead 18 and apositive terminal connected to an input side of an ignition or powercontrol switch 20.

One output lead from the ignition switch 20 is connected directly to apower terminal of the socket 23 and a further output lead from theignition switch 20 is connected to a signal terminal of the socket 23through two salt water indicator devices 21, 22. The third terminal ofthe socket 23 is connected to earth.

The salt water indicator devices are used to indicate the presence ofsalt water in the water separator 2 and comprise of an audible warningdevice in the form of a siren or buzzer 22 and a visual warning devicein the form of a light emitting diode or electric light 21.

If required the indication of the presence of water may be provided tomore than one location on the craft and the socket 24 shown in FIG. 5 isintended to replace the socket 23 so as to provide two outputs via theplugs 25, 26.

This enables the fuel supply system to supply an indication of thepresence of sea water in the fuel to two separate craft controlstations. As shown the plug 25 is intended to be connected via a cable27 to a flying bridge of the marine craft and the plug 26 is intended tobe connected via a cable 28 to a main deck control station.

The main deck control station may be located within a cabin of themarine craft or on a rear deck of the marine craft.

Each of the control stations would be provided with at least one of thetwo types of indication device and preferably with both.

Operation of the fuel control system is as follows. When the ignitionswitch is turned on and the engine is running fuel is pumped from thereservoir 1 via the water separator 2 by the low pressure fuel pump orlift pump 3 and then through the filter 4 to the distributor pump 5. Thedistributor pump 5 increases the pressure of the fuel and supplies it ina pre-determined sequence to the fuel injectors 6.

As the fuel passes through the water separator 2 the speed of flow ofthe fuel is greatly reduced because of the much greater flow areaprovided by the closed vessel and the presence of the baffles 10, 11.This allows any salt water mixed in with the fuel to separate out anddue to its higher specific gravity settle in the bottom of the closedvessel.

Initially the water separator is full of fuel but eventually, the levelof the salt water in the closed vessel will rise to the pre-determinedlevel at which point a circuit is made within the sensor 13 and a signalis sent via the signal lead to the buzzer 22 causing it to produce anaudible sound and to the electric lamp 21 causing it to illuminate.

This indicates to an operator of the marine craft that the level of saltwater collected by the water separator 2 has reached a level wheredraining is required.

At the next convenient opportunity the drain plug can then betemporarily removed to drain off the collected salt water.

After draining off the salt water the water separator 2 will once againbe full of fuel and the sensor 13 will be immersed in the fuel. Becausethe fuel has a lower electrical conductivity than salt water it will notcause the sensor 13 to send a signal to the indicator devices.

The process will then repeat with successive cycles of water collectionand emptying.

It will be appreciated by a person skilled in the art that the inventionis not limited to the specific embodiment described herein and thatvarious modifications or alternatives could be constructed withoutdeparting from the scope of the invention.

For example, the invention is equally applicable to marine craft havingmore than one engine fed from a common fuel tank or to marine crafthaving more than one fuel tank to feed one or more engines.

Similarly, the invention is not limited to the fuel injection meansdescribed herein but is applicable to other forms of fuel meteringdevice and to spark ignited as well as diesel engines.

1. A marine fuel supply system to supply liquid fuel to an internalcombustion engine of a marine craft, the fuel supply system comprising areservoir to store the liquid fuel, at least one fuel pump to pump fuelfrom the reservoir to the engine and at least one sensor located betweenthe reservoir and the engine wherein the or each sensor is arranged todetect the presence of sea water in the fuel and provide an indicationto an operator of the marine craft.
 2. A fuel supply system as claimedin claim 1 in which the presence of sea water is indicated by an audiblewarning device.
 3. A fuel supply system as claimed in claim 1 in whichthe presence of sea water is indicated by a visual warning device.
 4. Afuel supply system as claimed in claim 1 in which the indication of thepresence of water is provided to more than one location on the marinecraft.
 5. A fuel supply system as claimed in claim 1 in which the oreach sensor is located between an outlet from the reservoir and an inletto a fuel pump.
 6. A fuel supply system as claimed in claim 5 in whichthe fuel supply system further comprises of a fuel filter locatedbetween the fuel pump and the engine.
 7. A fuel supply system as claimedin claim 1 in which the system has a low pressure fuel pump connected toan outlet from the reservoir and a high pressure fuel pump connected tothe low pressure fuel pump to supply fuel at high pressure to the engineand the or each sensor is located between the outlet from the reservoirand the low pressure fuel pump.
 8. A fuel supply system as claimed inclaim 7 in which a fuel filter is located between the low pressure fuelpump and the high pressure fuel pump.
 9. A fuel supply system as claimedin claim 1 in which the or each sensor is mounted near to the bottom ofa water separator used to separate sea water from the liquid fuel.
 10. Afuel supply system as claimed in 9 in which the water separatorcomprises of a closed vessel having an upper wall, a lower wall, atleast one side wall, an inlet to the closed vessel and an outlet fromthe closed vessel.
 11. A fuel supply system as claimed in 10 in whichthe inlet to the closed vessel and the outlet from the closed vessel areconnected to the upper wall of the closed vessel.
 12. A fuel supplysystem as claimed in claim 10 in which there is at least one baffleplate interposed between the inlet to the closed vessel and the outletfrom the closed vessel.
 13. A fuel supply system as claimed in claim 12in which there is at least one baffle plate extending downwardly fromthe upper wall into the closed vessel at a position between the inlet tothe closed vessel and the outlet from the closed vessel.
 14. A fuelsupply system as claimed in claim 12 in which there is a baffle plateextending outwardly from the or one side wall of the closed vessel inclose proximity to the outlet from the closed vessel.
 15. A fuel supplysystem as claimed in claim 10 in which an air bleed device is fitted tothe upper wall.
 16. A fuel supply system as claimed in claim 10 in whicha drain plug is fitted to the lower wall of the closed vessel.
 17. Afuel supply system as claimed in claim 10 in which at least one sensoris fitted to the or one of the side walls of the closed vessel in closeproximity to the lower wall.
 18. A fuel supply system as claimed inclaim 10 in which at least one sensor is fitted to the lower wall of theclosed vessel.
 19. A fuel supply system as claimed in claim 17 in whichthe or each sensor is located such that when sea water reaches apredetermined level in the closed vessel the indication is provided tothe operator.
 20. A marine craft having at least one internal combustionengine and at least one fuel supply system as claimed in claim
 1. 21. Amarine craft as claimed in claim 20 in which the fuel supply system isarranged to supply an indication of the presence of sea water in thefuel to at least two separate craft control stations.
 22. A marine craftas claimed in claim 21 in which one of the control stations is a flyingbridge.
 23. A marine craft as claimed in claim 22 in which the craft hastwo control stations and the other control station is a main deckcontrol station.
 24. (canceled)
 25. (canceled)
 26. A water separator foruse in a marine fuel supply system to separate sea water from fuelcomprising a closed vessel having an upper wall, a lower wall, at leastone side wall, an inlet to the closed vessel and an outlet from theclosed vessel.
 27. (canceled)